Deletion of approximately 3 kb of upstream sequence, the translation initiation site and the majority of the coding sequence of cmpy.
Deletion of cmpy resulting from FLP-catalyzed recombination using the FRT-containing transposons PBac{WH}cmpyf02482 and PBac{WH}f01736.
The amplitude and frequency of spontaneous miniature excitatory junction potentials (mEJPs) at the neuromuscular junction is not significantly different from controls in homozygous larvae. However, there is a significant decrease in evoked EJP amplitude and quantal content in the homozygotes.
Homozygous larvae show defects in synaptic vesicle cycling (as assayed using uptake and unloading of the dye FM1-43), showing modest defects in endocytosis and more marked defects in exocytosis.
cmpyΔ8 homozygous mutants are viable, although females are sterile.
cmpyΔ8 homozygotes do not exhibit defects in neuronal cell fate acquisition or axon guidance.
cmpyΔ8 homozygotes display a 52% increase in the number of boutons at neuromuscular junction (NMJ) 6/7 and a 57% increase in type I boutons at NMJ 4. cmpyΔ8/Df(3L)BSC452 larvae show a comparable phenotype.
cmpyΔ8 mutant boutons tend to be smaller than those of wild type.
cmpyΔ8 mutants display a 2.9-fold increase in the number of satellite boutons at NMJ 4.
cmpyΔ8 mutant NMJs contain more active zones, but the percentage increase is comparable to that in bouton number, such that the active zone density remain constant. The assembly of periactive zones appears normal.
cmpyΔ8 has type I bouton | increased number | third instar larval stage phenotype, suppressible | partially by gbb1/gbb[+]
cmpyΔ8 has type I bouton | increased number | third instar larval stage phenotype, suppressible | partially by Mad[+]/Mad1
cmpyΔ8 has type I bouton | increased number | third instar larval stage phenotype, suppressible | partially by witA12/wit[+]
cmpyΔ8 has type I bouton | increased number | third instar larval stage phenotype, suppressible by gbbRNAi.UAS.cBa/Scer\GAL4Toll-6-D42
cmpyΔ8, witA12 has type I bouton | third instar larval stage phenotype
The ability of gbbScer\UAS.cKa expressed under the control of Scer\GAL4Toll-6-D42 to rescue the electrophysiological defects seen at the neuromuscular junction in gbb1/gbb2 larvae is impaired but not completely abolished if the larvae are also homozygous for cmpyΔ8.
The neuromuscular junction expansion phenotype seen in cmpyΔ8 mutants is partially suppressed when animals are also heterozygous for gbb1, Mad1 or witA12.
witA12, cmpyΔ8 double mutants show a 44% reduction in bouton number at neuromuscular junction 4, thereby phenocopying the neuromuscular junction undergrowth displayed by wit single mutants.
Scer\GAL4D42-mediated expression of gbbdsRNA.Scer\UAS.cBa suppresses the neuromuscular junction expansion phenotype seen in cmpyΔ8 mutants.
cmpyΔ8 is rescued by cmpyUAS.Tag:MYC/Scer\GAL4Toll-6-D42
cmpyΔ8 is rescued by Scer\GAL4Toll-6-D42/cmpyUAS.C.Venus
cmpyΔ8 is rescued by cmpyUAS.N.Venus/Scer\GAL4Toll-6-D42
cmpyΔ8 is rescued by cmpyUAS.cJa/Scer\GAL4Toll-6-D42
cmpyΔ8 is partially rescued by cmpyUAS.cJa/Scer\GAL4elav.PU
cmpyΔ8 is partially rescued by cmpyUAS.cJa/Scer\GAL4Toll-6-D42
Expression of either cmpyScer\UAS.T:Hsap\MYC, cmpyScer\UAS.C.T:Avic\GFP-YFP.Venus or cmpyScer\UAS.N.T:Avic\GFP-YFP.Venus under the control of Scer\GAL4Toll-6-D42 rescues the neuromuscular junction overgrowth phenotype seen in cmpyΔ8 larvae.
Expression of cmpyScer\UAS.cJa under the control of Scer\GAL4Toll-6-D42 rescues the reduction in evoked excitatory junction potential amplitude and in quantal content which is seen at the neuromuscular junction in homozygous cmpyΔ8 larvae.
Scer\GAL4D42-mediated overexpression of cmpyScer\UAS.cJa in a cmpyΔ8 background fully rescues bouton number at neuromuscular junction (NMJ) 4 whereas overgrowth is reduced from 52% to 9% at NMJ 6/7. Comparable rescue is observed when Scer\GAL4elav.PU is used.
